Amebicidal compositions



AMEBICIDAL COMPOSITIONS Max C. McCowen, Indianapolis, Ind., assignor to Lilly and Company, Indianapolis, Ind., a corporation of Indiana No Drawing. Application November 18, 1954 Serial No. 469,863

Claims. (Cl. 167-65) This invention relates to amebicidal compositions and more particularly to synergistic combinations of erythromycin and certain other amebicidal agents.

Erythromycin is an antibiotic substance which has been isolated from artificial nutrient culture media upon which the micro-organism Streptomyces eryzhreus has been grown. It is a useful and effective therapeutic agent for treatment of infections caused by Gram-positive organisms, and has also been found to be useful in the treatment of amebiasis.

When used therapeutically in the treatment of disease caused by amebic parasites, erythromycin must be employed in relatively large doses in order to secure effective results. Thus amounts of erythromycin ranging up to 400 mg. daily have been given for the treatment of amebiasis.

Certain other substances which have commonly been used for the treatment of amebiasis have likewise been required in relatively large dose amounts. For example, the arsenical drugs carbarsone and thiocarbarsone are generally administered thereapeutically in doses ranging up to 500 mg. per day for a course of medication of ten days. Because these compounds are slowly excreted, rest periods are imperative to prevent cumulative toxic effects. Another effective amebicide is fumagillin, an antibiotic substance which is isolated from culture media upon which the micro-organism Aspergillus fumigatus has been grown. While fumagillin is a useful amebicide, having an egect on amebic parasites at relatively low dose levels, nevertheless, doses up to 200 mg. of fumagillin daily have heretofore been employed in an elfort to bring about the cure of acute amebiasis. When such doses of this agent are given, untoward toxic symptoms may appear and generally require cessation of therapy.

It is an object of this invention to provide amebicidal compositions which are therapeutically effective in relatively low dosage. It is a further object of this invention to provide therapeutically useful amebicides which are substantially free from objectionable side effects. Other objects of the invention will be apparent from the disclosure made herein.

It has been found that by combining erythromycin with an amebicide of the group consisting of carbarsone, thiocarbarsone and fumagillin, highly efiective compositions are obtained for use in the treatment of amebiasis. The agents, when combined, are synergistic: for example, the amount of erythromycin employed for therapeutic purposes in amebiasis can be reduced to one tenth or less of the amount of the usual therapeutic dose of erythromycin, while the other amebicides can be reduced in amount to one half or less of the normal therapeutic dose. The compositions are therefore therapeutically effective in dose amounts which are far less than would be expected to be required. Furthermore, because of the small quantity of each amebicidal agent which is present, the possibility of adverse side effects is substantially completely eliminated.

2,922,743 Patented Jan. 26, 1960 ice As an illustration of the synergistic amebicidal activity of the compositions of this invention, there is set forth in Table 1 hereinafter the result of experiments carried out in rats infected with Endamoeba histolytica. Young ratswere selected because the acute infection thus produced 7 is more severe than in older rats, therefore providing more stringent experimental conditions. In the investigation, rats which were twenty-one days old and weighed from 30-35 g. were inoculated intracecally with cultures of Endamoeba histolytica strain NIH 200. Eighteen hours later, they were treated orally with various amebicides and combinations of amebicides as noted hereinafter. I

From six to ten rats were treated on each dose level and four doses were given to each rat at regular intervals over a period of two days. Forty-eight hours after the last dose had been given, the rats were sacrificed, the

cecum of each rat was removed and the cecal contents f of inoculated, untreated rats were used as controls. The. results observed were analysed statistically by the Chi square method to determine the probability that the parasites were cleared from the animal. are set forth in the following table. Thetotal dose of each drug and combination of drugs given is set forth, togetherwith the effect of the drug or combination ex pressed as cleared when the Chi-square probability values were 1 percent or less, or not cleared when those values were greater than 1 percent. In the case of lower dose levels of fumagillin, the results were such as to indicate partial clearance, with Chi-square probability of 5 percent at the levels indicated,.and this is recorded as such here, since fumagillin, as is known, has some effect upon Endamoeba histolyticz'a at lower dose levels, without bringing about definite elimination of the organisms.

While the relative amounts of each of the agents used in the new synergistic amebicidal compositions of the inventioncan be varied, and are reduced to quantities which are substantially less than those required for effective results in the case of each individual'compound, it is preferred to use in the new compositions one portion comprising about parts of erythromycin combined with asecond portionof about 100 to 2000 parts of carbarsone, or about 50 to 500 parts of thiocarbarsone, or about-1 to 3 partsof fumagillin.

The compositions of the invention can be used therapeutically in various pharmaceutical forms. Thus, they The results Example J.Preparatin of tablets containing erythromycin and'carbarsone The following ingredients are employed: Grams Erythromycin 1500' Carbarsone 1500 Starch v 1750 Magnesium stearate 65 The erythromycin. and, carbarsone are thoroughly mixed with about 1450 g. of the starch. The mixture is granulated with, a, thin paste. composed of about 175 g. of the starch with sufficient, water. The granules thus produced are mixed with the remainder of the starch, and the magnesium stearate, and. compressed into tablets having a, total Weight of aboutv 4.75 mg. About ten thousand tablets, each containing 150 mg. of erythromycin and 150 mg. of, carbarsone, are produced. 7

Alternatively, the tablets are prepared using part of the starch and 'the erythromycin to form compressed base tablets containing only the erythromycin. These tablets are placed in a coating pan and the carbarsone and. the remainder of the starch are added thereto. With the pan rotating, aqueous gum acacia is added to cause the, carbarsone and starch to adhere to the erythromycin tablets. In this way, a tablet is produced which contains as acore 150 mg. of erythromycin, and as an outer layer 150, mg. of carbarsone. An additional sugar coating may be applied in the usual. way if. desired, to provide protection and for pharmaceutical elegance. a

For treating amebiasis, the tablets are administered orally in such amount and for such length of time as is necessary to clear the infection.

'Example 2.Preparati'on of a tablet containing erythromycin and thioearbarsone The following ingredients are employed: Grams Erythromycin 125 Thiocarbarsone 625 Starch 480 Magnesium stearate The erythromycin and carbarsone are thoroughly mixed with about 330g of the starch. A thin paste is prepared by mixing about 100g. of the starch with suflicient Water, and the previously prepared mixture of erythromycin, thiocarbarsone andstarchis granulated with the paste. The granules thus produced: are mixed with the remainder of the starch. and the magnesium stearate, and the whole is compressed into tablets having a total weight of about 500 mg, using a- ;-inch die on the usual tableting The erythromycin and thiocarbarsone are mixed with aboutp67 g. of: starch, and. the. mixture is granulated with athin' paste containing g. of starch. The granules are mixed with the remaining starch and the: magnesium stearate and compressed. on. at tableting machine using -inch; dies, to produce. about. one thousand'tablet's 4 weighing about 264 mg. each, and containing about 100 mg. of erythromycin and 50 mg. of triocarbarsone.

Example 4.Preparatz'0n of tablets containing erythromycin and fumagillz'n The following ingredients are employed. G. Erythromycin 300 Fumagillin 2.5 Lactose 120 Starch 222 Talc 10 Magnesium stearate 5 Example 5.Preparation of tablets containing eirylhromycin and fumagillin The following ingredients are employed. G. Erythromycin 365 Fumagillinll.2 Lactose W. 100 Starch 166 Talc 5 Magnesium stearate 2 The erythromycin and fumagillin' are mixed with the lactose-and about 50 g. of the starch. The mixture is granulated with a paste prepared from 62.5 g. of the starch, and the granules are mixed with the remainder of the starch and the magnesium stearate. The mixture of all of the ingredients is then compressed into tablets havingatotal weight of about 264 mg. each, using a 7 inch die on the usual tableting machine. tablets, each containing about 150 mg. of erythromycin and 415' mg. of fumagillin, are produced.

I claim:-

' 1. A pharmaceutical composition comprising in combination, about 100 parts. of erythromycin and a member selected from the group consisting of about 100 to 2000 parts of carbarsone, SO'to 500 parts of thiocarban' sone and l to- 3 parts of fumagillin.

2. A pharmaceutical composition comprising one part of erythromycin and from about 1 to 20 parts of carbarsone.

3. A pharmaceutical composition comprising 100 parts of erythromycin and about 1 to 3 parts of fumagillin.

4. A pharmaceutical composition comprising 10 parts of erythromycin and 5 to 50 parts of thiocarbarsone.

5. A synergistic amebicidal therapeutic composition comprising in combination about 100 parts of erythromycin and a member selected from the group consisting of about 100 to 2000 parts of carbarsone, about 50 to 500 parts of thiocarb'arsone, and about 1 to'3 parts of I iumagillin, dispersed in a pharmaceutical extending medium.

References Cited in the file of this patent McCowen. et al: Efiects of Erythromycin Against Certain' Parasitic- Organisms, Am. I. Tropical Med, vol. 2, No.- 2, March. 1953, pp. 212-218.

(Other references on following page) About 2500' 5 6 Anderson et al.: Antibiotic synergism in Amebiasis, Ch l g g ll g g g m kasq'gsntibiotics and J. T 1 Med., vol. 3, No. 2, March 1954, emot ecem PP 1261. roplca pp Mc CoWen: Fumaglllin gH-3), a New Antibiotic with Welch: Antibiotic Therapy, Med. Encycl. Inc., N.Y., gsg Properties? Sclence, 1951, P- 202 1954, pp. 163-166, 170, 480-492. 5 an Powell: Lab. Studies of Combinations of Several ggfi g $321528:ggfxggg gggfl ggflgi Antimicrotic Agents, Antibio. and Chemotherapy, July Med Ma 1951 162 1953, pp. 701-708. Y PP- Science News Letter, Antibiotic Available for Amebic 1o Dysentery, Feb. 14, 1953, p. 99. 

5. A SYNERGISTIC AMEBICIDAL THERAPEUTIC COMPOSITION COMPRISING IN COMBINATION ABOUT 100 PARTS OF ERYTHROMYCIN AND A MEMBER SELECTED FROM THE GROUP CONSISTING OF ABOUT 100 TO 2000 PARTS FROM THE GROUP CONSISTING 500 PARTS OF THIOCARBARSONE, AND ABOUT 1 TO 3 PARTS OF FUMAGILLIN, DISPERSED IN A PHARMACEUTICAL EXTENDING MEDIUM. 